World timepiece

ABSTRACT

A world timepiece having means for controlling the time correction of the fundamental time that the fundamental time is interlocked to the time of a region having time difference when the correction amount is shorter than a time-differential unit time (thirty minutes or one hour), and is not interlocked when the correction amount is equal to the multiple of the time-differential unit time.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a world timepiece which is capable ofdisplaying the time of a particular region having time difference.

2. Description of the Prior Art

World timepieces have heretofore been constituted at least by a worldtime mode portion that displays the time of a selected region havingtime difference and a home time mode portion that displays a fundamentaltime. The fundamental time stands for a time of one of the regions whichis designated as a home time. Therefore, the fundamental time is limitedto a time that can be displayed in the world time mode.

In a world timepiece which displays the time of a particular regionhaving a time difference, the fundamental time stands for a time of thatregion where a home time is designated. Therefore, it is not allowed toset the fundamental time to a time other than the time of thepredetermined particular region having time difference. Namely, it isnot allowed to use the world timepiece in the regions other than theparticular region having time difference.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a world timepiecewhich is allowed to set the fundamental time to a time other than thetime of the particular region having time difference.

According to the present invention, provision is made of means forcontrolling the time correction of the fundamental time so that thefundamental time is interlocked to the time of a region having timedifference when the correction amount is shorter than atime-differential unit time (for example, one hour or 30 minutes), andis not interlocked when the correction amount is equal to the multipleof the time-differential unit time.

According to a world timepiece which displays the time of a particularregion having time difference based upon the above-mentioned method, thefundamental time can be set to the time of a region other than aparticular region having time difference without being limited to thetime of the particular region stored in the memory means. Therefore, thetimepiece can be used in a region having a time difference other thanthe particular region having time difference which is preset in theworld timepiece.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating an embodiment of the presentinvention;

FIG. 2 is a block diagram illustrating in detail the processor and theperiphery thereof shown in FIG. 1; and

FIG. 3 is a flow chart illustrating the procedure of data processingexecuted according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

An embodiment of the invention will now be described in conjunction withthe drawings. FIG. 1 is a block diagram which illustrates an embodimentof the present invention, wherein reference numeral 1 denotes anoscillation circuit including a quartz oscillator as a source ofoscillation, reference numeral 2 denotes a frequency-dividing circuitwhich divides the frequency of outputs of the oscillation circuit 1,reference numeral 3 denotes clock generating means which generatestiming clock signals necessary for operating the whole system inresponse to the outputs of the frequency-dividing circuit 2, referencenumeral 4 denotes switch input control means which controls the switchinput depending upon the timing determined by the clock generating means3, reference numeral 5 denotes a processor which calculates and controlsoutputs for a ROM 6, for a RAM 7, and for motor drive means 8 accordingto the outputs of the clock generating means 3 and switch input controlmeans 4, reference numeral 6 denotes the ROM that stores the instructionin which operation procedure of the timepiece is programmed, 7 denotesthe RAM that temporarily stores the time data or the like, and referencenumeral 8 denotes the motor drive means that drives the hands.

FIG. 2 is a block diagram of a circuit which illustrates in detail theprocessor 5 and the periphery thereof, and FIG. 3 is a flow chart of theprocessing executed by the processor 5.

The RAM 7 circuit is constituted by counting means 9 for counting theseconds of a fundamental time, counting means 10 for counting theminutes of the fundamental time, counting means 11 for counting thehours of the fundamental time, memory means 12 for storing the minute ofalarm, memory means 13 for storing the hour of alarm, counting means 14for counting the minutes of the world time, counting means 15 forcounting the hours of the world time, memory means 16 for storingregions of the world time, memory means 17 for storing the correctionamount of the fundamental time, and memory means 18 for storing thepresently displayed time information. The RAM, motor driving means 21,controlling means 22 that controls the switch input, and memory means 23that stores regions having time difference and the time differences, areconnected to CPU means 20 (hereinafter referred to as CPU) that executesthe operation via a bus line 19.

Operation of the thus constructed embodiment will now be described. Inresponse to 1-Hz signals produced by the clock generating means 3 shownin FIG. 1, the data of counting means 9 that counts the seconds of thefundamental time is read, via the bus line 19, by the CPU 20 where data"1" is added thereto. The data that is shorter than 60 seconds isstored, via the bus line 19, in the counting means 9 that counts theseconds of the fundamental time. The data that is longer than 60seconds, on the other hand, is rewritten as data 0 and is stored, viathe bus line 19, in the counting means 9 that counts the seconds of thefundamental time. When a carry has developed in the data, the upperdigit is read by the CPU 20 and is processed in the same manner as theabove-mentioned procedure that counts the seconds of the fundamentaltime. When the digits greater than the digit of minute of thefundamental time are counted, the same processing is executed even forthe minute of the world time and the hour of the world time. Then theCPU 20 compares the data of the memory means 18 that stores thepresently displayed time information with the data after it isprocessed. When it is necessary to move the hands, the CPU 20 sendsdata, via the bus line 19, to the motor driving means 21 that drives themotor, whereby the hands are moved by the output of the motor drivingmeans 21 that drives the motor. Procedures of these operations are allstored in the ROM 6 shown in FIG. 1.

In the system which is ordinarily operated as described above, when amode for correcting the fundamental time is assumed due to the operationof the switch, the processing of the flow chart of FIG. 3 is carriedout.

In FIG. 3, symbol SW1 denotes a lock/unlock switch, SW2 denotes a switchfor correcting the time indication in the forward direction, and SW3denotes a switch for correcting the time indication in the reversedirection. These switches are connected to the controlling means 22 (notshown) that controls the switch input. Symbol (CNT) denotes the contentof the memory means 17 that stores the correction amount of thefundamental time and that is reset when the mode for correcting thefundamental time is assumed. When the switch is manipulated, the outputof the controlling means 22 that controls the switch input is sent, viathe bus line, to the CPU 20, whereby the processing is carried outstarting from the step A as shown in FIG. 3 under the control of the CPU20. When the SW2 is operated once, one minute is added to thefundamental time and data "1" is added to the data of (CNT). When theSW3 is operated once, one minute is subtracted from the fundamental timeand 1 is subtracted from the data of (CNT). The procedure of arithmeticprocessing will now be described in conjunction with the flow chart.

When the SW2 is operated, a step B discriminates the input from the SW2and the program proceeds to a step C where the data of the countingmeans 10 that counts the minutes of the fundamental time is read, viathe bus line 19, by the CPU 20 that adds the data "1" thereto. The datathat becomes longer than "60" is rewritten as "0" and is stored, via thebus line 19, in the counting means 10 which counts the minutes of thefundamental time. The data that is shorter than "60" is stored, via thebus line 19, in the counting means 10 which counts the minutes of thefundamental time. When a carry has developed in the date, the sameprocessing is effected for the upper digit. The program then proceeds toa step D where the data of (CNT) is read, via the bus line 19, by theCPU 20 that adds the data "1" thereto. Then, a step E discriminateswhether the data is greater than "30" or not. The data that is greaterthan or equal to "30" is rewritten as "0" in a step F and is storedagain in the memory means 17. The data that is smaller than "30" isstored in the memory means 17 via bus line 19, and the program returnsto the starting step A. When the SW3 is operated, the program proceedsfrom the step B to a step G where one minute is subtracted from the dataof hour and minute of the fundamental time like the case when the SW2 isoperated, and data "1" is subtracted from the (CNT) data in a step H.

Then, a step I discriminates whether the (CNT) data has a negative valueor not. When the (CNT) data has a negative value, a step J changes thedata to "29". When the (CNT) data is greater than "0", the data isstored in the memory means 17 and the program returns to the startingstep A. The above-mentioned processings are repeated every time when theSW2 and SW3 are operated.

In the above-mentioned processing, the data of (CNT) remains within arange of "0" to "29" no matter how much amount the fundamental time iscorrected because the data of (CNT) is divided by an equal timedifference data "30" to calculate the remainder. The fundamental time iscorrected to a desired time by operating the SW2 and SW3, and then theSw1 is operated to execute another processing starting with the step B.A step K discriminates the data of (CNT). When the data is smaller thanor equal to "15", a step L adds the data of (CNT) to the hour and minutedata of the world time. When the data of (CNT) is greater than "15", onthe other hand, a step M stores in the (CNT) a value that is obtained bysubtracting the data of (CNT) from "30", and a step N subtracts the dataof (CNT) from the hour and minute data of the world time. Finally, astep 0 executes the processing to shift the mode of correcting thefundamental time to the ordinary mode of the fundamental time.

When the fundamental time is corrected in the fundamental timecorrecting mode in accordance with the present invention as describedabove, the world time is not interlocked or related to a portion of thecorrection amount larger than the time-differential unit time or theequal time difference (which in this embodiment is set to be thirtyminutes, but may be one hour). Therefore, the fundamental time can beset to any time other than the world times the regions or time zonesarranged progressively at the equal time difference stored in the memorymeans 23. The world time, however, is interlocked to the correctionamount (which in this embodiment lies over a range of -14 minutes to +15minutes) which is shorter than the time-differential unit time.Therefore, the world time can also be corrected simultaneously at thetime when the fundamental time that goes slow or fast is corrected. Inthe world timepiece which stores and displays the time of a particularregion having time difference, therefore, the standard time of a regionother than the particular region can be set as the reference time.Therefore, the timepiece can be used in any region.

What is claimed is:
 1. A world timepiece comprising:an oscillationcircuit including a quartz oscillator as a source of oscillation forproducing an output signal having a given frequency; afrequency-dividing circuit for dividing the frequency of the outputsignal of the oscillation circuit to produce divided signals; means forgenerating timing clock signals in response to the divided outputsignals of the frequency-dividing circuit; means for counting afundamental time in response to the timing clock signals; means forstoring a plurality of regions having time differences in terms of atime-differential unit time and for storing the time differences; meansfor counting a world time of a given region among the plurality ofregions having time differences in response to the timing clock signals;external operation means for inputting a correction amount of thefundamental time; means for storing data representative of thecorrection amount of the fundamental time inputted by the externaloperation means; counting means for counting the correction amount ofthe fundamental time to obtain a count value calculated by subtracting amultiple of the time-differential unit time from the correction amountof the fundamental time, said counting means including comparing meansfor generating a resetting signal for resetting the counting means eachtime the count value becomes the same as that of the time-differentialunit time; and means for correcting the world time in accordance withthe count value.
 2. A world timepiece as claimed in claim 1; including aplurality of hands for indicating the fundamental time or the world timeof a given region; means for storing data representative of thefundamental time and the world time to be indicated by the hands; astepping motor for intermittently rotating the hands; and means fordriving the stepping motor.
 3. A world timepiece as claimed in claim 1;wherein the time-differential unit time is set to be thirty minutes. 4.A world timepiece as claimed in claim 1; wherein the time-differentialunit time is set to be one hour.
 5. A timepiece for indicating worldtimes assigned to corresponding time zones and progressively arrangedrelative to each other at an equal time difference according to the timezones and for indicating a home time settable between adjacent worldtimes, the timepiece comprising: means for producing a clock signal;first counting means for counting a home time in response to the clocksignal; first memory means for storing the counted home time; firstcorrecting means for correcting the stored home time by a givencorrection amount of time; second counting means for counting a worldtime assigned to a given time zone in response to the clock signal;second memory means for storing the counted world time; means forarithmetically processing the correction amount of time to divide thesame by the equal time difference to thereby calculate a remainder;second correcting means for correcting the stored world time accordingto the calculated remainder to thereby maintain the assignment of thecorrected world time to the corresponding time zone after the correctionof the home time; and indicating means for indicating the stored homeand world times.
 6. A timepiece as claimed in claim 5; wherein theindicating means includes a plurality of time-indicating hands; and astepping motor for stepwisely rotating the time-indicating hands toindicate the home and world times.
 7. A timepiece as claimed in claim 5;including means for progressively arranging world times at an equal timedifference of thirty minutes.
 8. A timepiece as claimed in claim 5;including means for progressively arranging world times at an equal timedifference of one hour.